Integrating Different Biological Evidence Around Some Microevolutionary Processes: Bottlenecks and Asian-American Arctic Gene Flow in the New World Settlement

Abstract

Excepting some specific efforts, most of the mainstream debate around the Americas' settlement has been directed by specialists dealing with partial evidence. Thus, discussions have been confined to particular academic and scientific environments with limited interchange among archeologists, physical anthropologists, linguists, geneticists, geologists, paleontologists, and so on. As a consequence, integrative views about a process that is complex by definition have been scarce and driven by confrontation rather than by a search for common results. Still, an increasing number of specialists are attempting to integrate different types of data. In our view, a proper way to do this is to focus the discussion around evolutionary or cultural processes and the putative patterns that such processes could have generated in the different types of data, which in turn, depend on the nature of the data. In this way, the analyses and conclusions can be interpreted as "model-bound" rather than purely inferential. In this paper, we first provide a brief summary of main differences among the two main sources of biological informationgenetics and craniofacial size and shape-along with the main conclusions that the patterns of genetic and craniofacial variation provide. Furthermore, we exemplify the above-mentioned notion by discussing two particular processes and their hypothetical impact on genetic and craniofacial data: the influence of bottlenecks during the early dispersal and a putative zone of gene flow among Asian and American Circum-Arctic populations.Keywords Bottlenecks . Arctic gene flow . Skull shape . mtDNA . Y-chromosome . Autosomal markers . Native Americans Humans have always been curious about their origins back before the rise of civilization. However, only with the advent of science were widely accepted methods established in order to answer many issues regarding our own history. Archeology and paleontology have long offered theoretical tools and empirical evidence to support research on modern Homo sapiens origins and its extraordinary outof-Africa expansion and adaptive radiation to previously unoccupied continents (Collard et al. 2007;Foley and Lahr 2003;Lahr 1996;Rightmire et al. 2007;Stringer et al. 1995). This scenario, however, experienced a major revolution in the past century with the emergence of genetics and more recently, of molecular biology, because both disciplines have brought new tools to uncover the unregistered past of human populations (see recent examples in Blum and Jakobsson 2010;Rasmussen et al. 2010;Ray et al. 2009). Additionally, population and quantitative genetics provide a formal, proper framework to make inferences around the four central concepts of Darwinian thought (multiplication, heredity, variation, and competition by natural selection) and further concepts emphasized by modern evolutionary theory as well (stochastic factors, epigenesis, genomics, evolutionary development, geneculture coevolution, etc.). To sum up, a highly stimulating set of disciplines contributes ...

How strong was the bottleneck associated to the peopling of the Americas? New insights from multilocus sequence data

“…Despite many scientific efforts have been made to unveil the peopling of the Americas, several important questions are still elusive (see Salzano, 2007 ; Goebel et al , 2008 ; González-José and Bortolini, 2011 ; O’Rourke, 2011 ; Marangoni et al , 2014 for recent reviews). Since the classic tripartite hypothesis for the origin of Native Americans proposed by Greenberg et al (1986) , a range of migration theories have been put forward to account for the linguistic, genetic, and morphologic diversity of human populations in the New World (see Marangoni et al , 2014 ).…”

Contributions to a historical review of biological anthropology in Brazil from the second half of the twentieth century

“…More recently some geneticists have focused on the topic (anthropological genetics), proposing a new model that integrates morphological and molecular perspectives. Their findings can be read in the works of Gonzáles-José et al (2008), Gonzáles-José and Bortolini (2011) and in the review undertaken by Salzano (2011). Contributions have also come from paleopathology and paleoparasitology (Ferreira et al, 2008).…”

Geographic patterns of Early Holocene New World dental morphological variation

“…While this model still provides a viable explanation for the settlement of the Western Hemisphere (Estrada- Mena et al, 2010;Reich et al, 2012), recent advances in anthropological genetic sampling protocols, amplification techniques, and analytical approaches have provided more nuanced understandings of New World population structure. These include models that propose a single origin from an Asian source population isolated in Beringia prior to colonization of the Americas (Estrada- Mena et al, 2010;Fagundes et al, 2008;Kitchen et al, 2008;Mulligan et al, 2008;Schroeder et al, 2007Schroeder et al, , 2009Tamm et al, 2007;Wang et al, 2007), dual origin models (Gilbert et al, 2008;Rasmussen et al, 2010), and more complex scenarios involving one or more migrations from a heterogeneous source population -possibly via different migration routes -followed by bidirectional gene flow between Asia and the Americas that lasted several thousand years (González-José and Bortolini, 2011;Kumar et al, 2011;Mazières, 2011;O'Rourke and Raff, 2010;Perego et al, 2009Perego et al, , 2010Ray et al, 2010;Rubicz et al, 2010;Tamm et al, 2007). In addition, recent archaeological discoveries have largely supplanted the "Clovis First" model which dominated Paleoindian research for several decades (e.g., Adovasio and Pedler, 2004;Dillehay, 1997;Goebel et al, 2008;Waters et al, 2011) and which coincided strongly with the predictions of the tripartite model.…”

“…In addition, recent archaeological discoveries have largely supplanted the "Clovis First" model which dominated Paleoindian research for several decades (e.g., Adovasio and Pedler, 2004;Dillehay, 1997;Goebel et al, 2008;Waters et al, 2011) and which coincided strongly with the predictions of the tripartite model. Discoveries of Early Holocene skeletal material from South America, combined with advances in phenotypic data analysis better grounded in evolutionary processes, have also generated new views on the peopling of the Americas (e.g., de Azevedo et al, 2011;Gonzalez et al, 2010;González-José and Bortolini, 2011; José et al, 2001Mena L. et al, 2003;Neves et al, 2004Neves et al, , 2005Perez et al, 2007Perez et al, , 2009Pucciarelli et al, 2003Pucciarelli et al, , 2006Pucciarelli et al, , 2008Pucciarelli et al, , 2010.…”

“…Despite the historical importance of dental anthropology in the First Americans debate, recent synthetic surveys of the literature (e.g., Dillehay, 2009;Fiedel, 2004;Goebel et al, 2008;González-José and Bortolini, 2011;Mazières, 2011;O'Rourke, 2011;O'Rourke and Raff, 2010;Pitblado, 2011) indicate that dentition has lost its relevance in these discussions. In fact, the most recent literature review fails to include a single citation for papers using dental morphology as a basis for inferring New World population history (Pitblado, 2011).…”